Editing Metadata schema form editor all properties of tags are not visible

I have added a standard tag, and I can't make it require and single selection of tag. How can I make it required and single selection from the list of tags not multiple

I have added a standard tag, and I can't make it require and single selection of tag. How can I make it required and single selection from the list of tags not multiple
Enter your E-mail address. We'll send you an e-mail with instructions to reset your password.